About
Alnus formosana is a rapid-growing, deciduous tree that reaches heights of up to 20 meters. Its leaves are elongated and start off pink before maturing to a glossy green, ultimately dropping in autumn. In the spring, numerous male catkins appear, while the female woody cones remain attached to the branches throughout the winter months.
About the genus
Alnus comprises robust deciduous trees and sizable shrubs characterized by their rounded foliage and, during winter, noticeable catkins.
Growing conditions
- Sunlight
- Full sun
- Soil type
- Clay, Loam
- Soil pH
- Acid, Alkaline, Neutral
- Soil moisture
- Poorly-drained
- Aspect
- East-facing, North-facing, South-facing, West-facing
- Exposure
- Exposed, Sheltered
- UK hardiness
- H6
Plant details
- Plant type
- Trees
- Habit
- Spreading branched, Columnar upright
- Foliage
- Deciduous
- Height
- Higher than 12 metres
- Spread
- wider than 8 metres
- Time to full height
- 20-50 years
- Suggested uses
- Architectural
- Native to
- Taiwan
Care notes
- Cultivation
- It is a nitrogen-fixer so can grow on poor soil. Suited to river banks on permanently damp soil in good light. For more information see tree cultivation.
- Pruning
- Pruning group 1
- Propagation
- Propagate by hardwood cuttings or seed. For more advice see our information on how to propagate from seed (tree/shrub
- Pest resistance
- May be susceptible to alder leaf beetle, alder sucker and leaf-mining sawflies
- Disease resistance
- May be susceptible to phytophthora root rot and honey fungus